Improved bridge



N waited gieten4 H. S. MCDOWELL, OF OGLUMBUS, TEXAS.

Leners Patent No. "98,699, dated January 11, 1870. e

The Schedule referred to in these Letters Patent and making part of the same.

To all whom it may concern:

Beit known that I, H. S. MCDOWELL, of Columbus, in the county of Colorado, and State of Texas, have invented a new and useful Improvement in Bridges; and I do hereby declare that the following is a full, clear, and exact description thereof', which will enable othersskilled in the art to make and use the same, reference being had to the accompanyingv simplify the construction and increase the efficiency of Y the same.

Figure 1 represents a longitudinal sectional elevation of a span constructed according to my improvements; and

Figure 2 represents an end View, partly in section.

I make the top chords A in sections, .composed of any .preferred number of thin bars B of wood, set edgewise, and fitted at the ends against the joint castings C, from which the rods D, and `main and eounter-blaces F and E are suspended.

Thesecastings have under flanges G, wherever the lower edges of the bars B rest.

'They also have flanges H projecting between the bars, so as to separate' them at the sides.

The braces are connected to the said castings by bolts I, passing through ears K, projecting downward from the under sides; andthe suspending-rods D are connected by the same or similar bolts, passing through the widened parts of the` said castings, near thetop, in the cases where the said upper chords are bent at the joints. These bars are so fitted to the castings,

, that when the bolts which hold them to the castings are removed, they may be removed, each separately, and new ones putin their places. They are bolted laterally, by rods running across from one chord to the other, in a way common to other bridges.

The main-braces F and counter-braces E, I propose to make iu two parts, having joints at the centre, connected by met-al straps or clips L, so that they maybe separated by straining-bolts M,'as shown in the drawings, whereby they are great-ly stiliened.

For the main braces, I propose to use two sets, side by side, but suficiently separated for the 'counterbraces of only one set to pass between them.

At the lower ends of these `braces and the suspending-rods D, I suspend the transverse rods or axles N, to which the lo'wer chords O are also connected, and in which the longitudinal track-stringers P rest, in a way to dispense with the metal floor-timbers commonly used.-

These transverse rods I propose to strengthen between the ends by the bent bars Q, suspended from each end, and the braces S.

This construction of the. upper chords, which are intended to rise from Vthe abutments, so as t0 take the strain wholly or mostly at. the ends, very greatly relieves the lower chords, and enablesnie to make them. lighter and cheaper.

` It will be seen that the braces may be removed separately with great facility.

T represents straps or plates of metal connected to the transverse rods, with projecting points for the connection of the diagonal rods uniting the lower chords.

ll-Iaving thus described my invention,

AI claim as new, and desire to secure by'Letters Patentl. A bridge, provided with bars B, castings C, rods D, duplicate jointed braces E F, bolts M, plates L, and chords A O, all arranged asshown and described.

2..-The combination, with the axle-rods N, of the bent bars Q and braces S, substantially as specified.

f H. S. MGDOWELL.

VVitn esses:

J No. D. GILLMORE, FRED. BARNARD. 

